Same test getting much worse result on Windows 2019 Server(DC) than on Windows 2025 Server(DC)

[gaoyefei]

Test command: diskspd -eDISK_IO -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t16 "#1"
On 2019: write IOPS is 180K
On 2025: write IOPS is 349K

These are VMs on Google Compute Engine. I noticed that on 2019, the OS has 3 NUMA nodes for all 192 cores, but on 2025, it's only 1 node.

Detailed output:
2019:

C:\DISKSPD\amd64>diskspd -eDISK_IO -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t16 "#1"
WARNING: target access pattern will not be sequential, consider -si

Command Line: diskspd -eDISK_IO -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t16 #1

Input parameters:

        timespan:   1
        -------------
        duration: 300s
        warm up time: 10s
        cool down time: 0s
        random seed: 0
        path: '#1'
                think time: 0ms
                burst size: 0
                software cache disabled
                hardware write cache disabled, writethrough on
                performing write test
                block size: 4KiB
                using sequential I/O (stride: 4KiB)
                number of outstanding I/O operations per thread: 64
                threads per file: 16
                using I/O Completion Ports
                IO priority: normal

System information:

        computer name: testcase-1795364-1755272649-0
        start time: 2025/08/15 21:03:53 UTC

        cpu count:              192
        core count:             96
        group count:            3
        node count:             3
        socket count:           1
        heterogeneous cores:    n

        active power scheme:    High performance (8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c)

Results for timespan 1:
*******************************************************************************

actual test time:       300.00s
thread count:           16

Node | Group | Core | CPU |  Usage |  User  | Kernel |  Idle
--------------------------------------------------------------
    0|      0|     0|    0|  25.35%|   0.64%|  24.72%|  74.65%
    0|      0|     0|    1|  11.73%|   0.34%|  11.39%|  88.27%
    0|      0|     1|    2|  11.82%|   0.26%|  11.56%|  88.18%
    0|      0|     1|    3|  11.45%|   0.26%|  11.19%|  88.55%
    0|      0|     2|    4|  11.54%|   0.28%|  11.27%|  88.46%
    0|      0|     2|    5|  11.09%|   0.25%|  10.84%|  88.91%
    0|      0|     3|    6|  11.46%|   0.26%|  11.20%|  88.54%
    0|      0|     3|    7|  11.73%|   0.33%|  11.40%|  88.27%
    0|      0|     4|    8|  11.32%|   0.19%|  11.13%|  88.68%
    0|      0|     4|    9|  11.28%|   0.26%|  11.03%|  88.72%
    0|      0|     5|   10|  11.37%|   0.27%|  11.10%|  88.63%
    0|      0|     5|   11|  11.41%|   0.23%|  11.18%|  88.59%
    0|      0|     6|   12|  11.56%|   0.24%|  11.32%|  88.44%
    0|      0|     6|   13|  11.72%|   0.23%|  11.49%|  88.28%
    0|      0|     7|   14|  11.53%|   0.35%|  11.18%|  88.47%
    0|      0|     7|   15|  11.96%|   0.23%|  11.73%|  88.04%
    0|      0|     8|   16|   0.03%|   0.03%|   0.01%|  99.97%
    0|      0|     8|   17|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|     9|   18|   0.01%|   0.01%|   0.01%|  99.99%
    0|      0|     9|   19|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    10|   20|   0.02%|   0.01%|   0.01%|  99.98%
    0|      0|    10|   21|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    11|   22|   0.01%|   0.01%|   0.00%|  99.99%
    0|      0|    11|   23|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    12|   24|   0.01%|   0.00%|   0.01%|  99.99%
    0|      0|    12|   25|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    13|   26|   0.01%|   0.01%|   0.01%|  99.99%
    0|      0|    13|   27|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    14|   28|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    14|   29|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    15|   30|   0.01%|   0.00%|   0.01%|  99.99%
    0|      0|    15|   31|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    16|   32|   0.01%|   0.00%|   0.01%|  99.99%
    0|      0|    16|   33|   0.01%|   0.01%|   0.00%|  99.99%
    0|      0|    17|   34|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    17|   35|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    18|   36|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    18|   37|   0.01%|   0.00%|   0.01%|  99.99%
    0|      0|    19|   38|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    19|   39|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    20|   40|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    20|   41|   0.02%|   0.00%|   0.02%|  99.98%
    0|      0|    21|   42|   0.01%|   0.00%|   0.01%|  99.99%
    0|      0|    21|   43|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    22|   44|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    22|   45|   0.01%|   0.00%|   0.01%|  99.99%
    0|      0|    23|   46|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    23|   47|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    24|   48|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    24|   49|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    25|   50|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    25|   51|   0.01%|   0.00%|   0.01%|  99.99%
    0|      0|    26|   52|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    26|   53|   0.02%|   0.00%|   0.02%|  99.98%
    0|      0|    27|   54|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    27|   55|   0.01%|   0.01%|   0.00%|  99.99%
    0|      0|    28|   56|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    28|   57|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    29|   58|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    29|   59|   0.03%|   0.00%|   0.03%|  99.97%
    0|      0|    30|   60|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    30|   61|   0.03%|   0.01%|   0.02%|  99.97%
    0|      0|    31|   62|   0.00%|   0.00%|   0.00%| 100.00%
    0|      0|    31|   63|   0.03%|   0.00%|   0.03%|  99.97%
    1|      1|     0|    0|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     0|    1|  65.55%|   0.01%|  65.55%|  34.45%
    1|      1|     1|    2|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     1|    3|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     2|    4|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     2|    5|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|     3|    6|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     3|    7|   0.01%|   0.01%|   0.01%|  99.99%
    1|      1|     4|    8|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     4|    9|   0.01%|   0.01%|   0.00%|  99.99%
    1|      1|     5|   10|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     5|   11|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     6|   12|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     6|   13|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     7|   14|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     7|   15|   0.01%|   0.01%|   0.00%|  99.99%
    1|      1|     8|   16|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|     8|   17|   0.01%|   0.01%|   0.01%|  99.99%
    1|      1|     9|   18|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|     9|   19|   0.03%|   0.00%|   0.03%|  99.97%
    1|      1|    10|   20|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    10|   21|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    11|   22|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    11|   23|   0.31%|   0.00%|   0.31%|  99.69%
    1|      1|    12|   24|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    12|   25|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    13|   26|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    13|   27|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    14|   28|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    14|   29|   0.02%|   0.01%|   0.01%|  99.98%
    1|      1|    15|   30|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    15|   31|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    16|   32|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    16|   33|   0.01%|   0.01%|   0.00%|  99.99%
    1|      1|    17|   34|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    17|   35|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    18|   36|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    18|   37|   0.01%|   0.01%|   0.01%|  99.99%
    1|      1|    19|   38|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    19|   39|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    20|   40|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    20|   41|   0.01%|   0.01%|   0.00%|  99.99%
    1|      1|    21|   42|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    21|   43|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    22|   44|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    22|   45|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    23|   46|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    23|   47|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    24|   48|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    24|   49|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    25|   50|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    25|   51|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    26|   52|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    26|   53|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    27|   54|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    27|   55|   0.01%|   0.01%|   0.00%|  99.99%
    1|      1|    28|   56|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    28|   57|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    29|   58|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    29|   59|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    30|   60|   0.01%|   0.00%|   0.01%|  99.99%
    1|      1|    30|   61|   0.01%|   0.01%|   0.00%|  99.99%
    1|      1|    31|   62|   0.00%|   0.00%|   0.00%| 100.00%
    1|      1|    31|   63|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     0|    0|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     0|    1|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     1|    2|   0.01%|   0.00%|   0.01%|  99.99%
    2|      2|     1|    3|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     2|    4|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     2|    5|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     3|    6|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     3|    7|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     4|    8|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     4|    9|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     5|   10|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     5|   11|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     6|   12|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     6|   13|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     7|   14|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     7|   15|   0.01%|   0.01%|   0.00%|  99.99%
    2|      2|     8|   16|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     8|   17|   0.01%|   0.01%|   0.00%|  99.99%
    2|      2|     9|   18|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|     9|   19|   0.01%|   0.00%|   0.01%|  99.99%
    2|      2|    10|   20|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    10|   21|   0.01%|   0.00%|   0.01%|  99.99%
    2|      2|    11|   22|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    11|   23|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    12|   24|   0.01%|   0.00%|   0.01%|  99.99%
    2|      2|    12|   25|   0.01%|   0.00%|   0.01%|  99.99%
    2|      2|    13|   26|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    13|   27|   0.01%|   0.01%|   0.00%|  99.99%
    2|      2|    14|   28|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    14|   29|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    15|   30|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    15|   31|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    16|   32|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    16|   33|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    17|   34|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    17|   35|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    18|   36|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    18|   37|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    19|   38|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    19|   39|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    20|   40|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    20|   41|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    21|   42|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    21|   43|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    22|   44|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    22|   45|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    23|   46|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    23|   47|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    24|   48|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    24|   49|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    25|   50|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    25|   51|   1.35%|   1.18%|   0.17%|  98.65%
    2|      2|    26|   52|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    26|   53|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    27|   54|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    27|   55|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    28|   56|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    28|   57|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    29|   58|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    29|   59|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    30|   60|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    30|   61|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    31|   62|   0.00%|   0.00%|   0.00%| 100.00%
    2|      2|    31|   63|   0.00%|   0.00%|   0.00%| 100.00%
--------------------------------------------------------------
                      avg.|   1.39%|   0.03%|   1.35%|  98.61%

Total IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |     12252463104 |      2991324 |      38.95 |    9971.07 | #1 (2.44TiB)
     1 |     13934268416 |      3401921 |      44.30 |   11339.72 | #1 (2.44TiB)
     2 |     14006833152 |      3419637 |      44.53 |   11398.77 | #1 (2.44TiB)
     3 |     13967994880 |      3410155 |      44.40 |   11367.17 | #1 (2.44TiB)
     4 |     14036619264 |      3426909 |      44.62 |   11423.01 | #1 (2.44TiB)
     5 |     13951471616 |      3406121 |      44.35 |   11353.72 | #1 (2.44TiB)
     6 |     14000885760 |      3418185 |      44.51 |   11393.93 | #1 (2.44TiB)
     7 |     13981159424 |      3413369 |      44.44 |   11377.88 | #1 (2.44TiB)
     8 |     14063280128 |      3433418 |      44.71 |   11444.71 | #1 (2.44TiB)
     9 |     13951348736 |      3406091 |      44.35 |   11353.62 | #1 (2.44TiB)
    10 |     13943099392 |      3404077 |      44.32 |   11346.91 | #1 (2.44TiB)
    11 |     13935374336 |      3402191 |      44.30 |   11340.62 | #1 (2.44TiB)
    12 |     13925023744 |      3399664 |      44.27 |   11332.20 | #1 (2.44TiB)
    13 |     13943050240 |      3404065 |      44.32 |   11346.87 | #1 (2.44TiB)
    14 |     13977968640 |      3412590 |      44.43 |   11375.28 | #1 (2.44TiB)
    15 |     13956505600 |      3407350 |      44.37 |   11357.82 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:      221827346432 |     54157067 |     705.17 |  180523.30

Read IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     1 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     2 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     3 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     4 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     5 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     6 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     7 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     8 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     9 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    10 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    11 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    12 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    13 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    14 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    15 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:                 0 |            0 |       0.00 |       0.00

Write IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |     12252463104 |      2991324 |      38.95 |    9971.07 | #1 (2.44TiB)
     1 |     13934268416 |      3401921 |      44.30 |   11339.72 | #1 (2.44TiB)
     2 |     14006833152 |      3419637 |      44.53 |   11398.77 | #1 (2.44TiB)
     3 |     13967994880 |      3410155 |      44.40 |   11367.17 | #1 (2.44TiB)
     4 |     14036619264 |      3426909 |      44.62 |   11423.01 | #1 (2.44TiB)
     5 |     13951471616 |      3406121 |      44.35 |   11353.72 | #1 (2.44TiB)
     6 |     14000885760 |      3418185 |      44.51 |   11393.93 | #1 (2.44TiB)
     7 |     13981159424 |      3413369 |      44.44 |   11377.88 | #1 (2.44TiB)
     8 |     14063280128 |      3433418 |      44.71 |   11444.71 | #1 (2.44TiB)
     9 |     13951348736 |      3406091 |      44.35 |   11353.62 | #1 (2.44TiB)
    10 |     13943099392 |      3404077 |      44.32 |   11346.91 | #1 (2.44TiB)
    11 |     13935374336 |      3402191 |      44.30 |   11340.62 | #1 (2.44TiB)
    12 |     13925023744 |      3399664 |      44.27 |   11332.20 | #1 (2.44TiB)
    13 |     13943050240 |      3404065 |      44.32 |   11346.87 | #1 (2.44TiB)
    14 |     13977968640 |      3412590 |      44.43 |   11375.28 | #1 (2.44TiB)
    15 |     13956505600 |      3407350 |      44.37 |   11357.82 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:      221827346432 |     54157067 |     705.17 |  180523.30



ETW:
----

        Disk I/O
                Read: 0
                Write: 54166615


          ETW Buffer Settings & Statistics
--------------------------------------------------------
(KB)                           Buffers   (Secs)   (Mins)
Size  | Min |  Max  |  Free  | Written  | Flush    Age
138     384     406    384     61933         1        0

Allocated Buffers:      384
Lost Events:            0
Lost Log Buffers:       0
Lost Real Time Buffers: 0

2025:

C:\DISKSPD\amd64>diskspd -eDISK_IO -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t16 #1
WARNING: target access pattern will not be sequential, consider -si

Command Line: diskspd -eDISK_IO -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t16 #1

Input parameters:

        timespan:   1
        -------------
        duration: 300s
        warm up time: 10s
        cool down time: 0s
        random seed: 0
        path: '#1'
                think time: 0ms
                burst size: 0
                software cache disabled
                hardware write cache disabled, writethrough on
                performing write test
                block size: 4KiB
                using sequential I/O (stride: 4KiB)
                number of outstanding I/O operations per thread: 64
                threads per file: 16
                using I/O Completion Ports
                IO priority: normal

System information:

        computer name: testcase-148196-1755643804-0
        start time: 2025/08/19 23:37:20 UTC

        cpu count:              192
        core count:             96
        group count:            3
        node count:             1
        socket count:           1
        heterogeneous cores:    n

        active power scheme:    High performance (8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c)

Results for timespan 1:
*******************************************************************************

actual test time:       300.00s
thread count:           16

Group | Core | CPU |  Usage |  User  | Kernel |  Idle
-------------------------------------------------------
     0|     0|    0|   8.28%|   0.39%|   7.89%|  91.72%
     0|     0|    1|   7.60%|   0.48%|   7.12%|  92.40%
     0|     1|    2|   8.12%|   0.47%|   7.65%|  91.88%
     0|     1|    3|   7.42%|   0.43%|   6.99%|  92.58%
     0|     2|    4|  77.00%|   0.14%|  76.86%|  23.00%
     0|     2|    5|  33.13%|   1.21%|  31.92%|  66.88%
     0|     3|    6|   7.30%|   0.45%|   6.84%|  92.70%
     0|     3|    7|   7.11%|   0.34%|   6.78%|  92.89%
     0|     4|    8|   7.33%|   0.56%|   6.77%|  92.67%
     0|     4|    9|   7.12%|   0.46%|   6.66%|  92.88%
     0|     5|   10|   7.32%|   0.49%|   6.83%|  92.68%
     0|     5|   11|   7.10%|   0.45%|   6.65%|  92.90%
     0|     6|   12|   7.53%|   0.47%|   7.05%|  92.47%
     0|     6|   13|   7.16%|   0.37%|   6.79%|  92.84%
     0|     7|   14|   7.77%|   0.42%|   7.35%|  92.23%
     0|     7|   15|   7.58%|   0.41%|   7.17%|  92.42%
     0|     8|   16|   0.39%|   0.03%|   0.36%|  99.61%
     0|     8|   17|   0.34%|   0.07%|   0.27%|  99.66%
     0|     9|   18|   1.76%|   0.43%|   1.32%|  98.24%
     0|     9|   19|   0.31%|   0.01%|   0.30%|  99.69%
     0|    10|   20|   0.46%|   0.05%|   0.41%|  99.54%
     0|    10|   21|   0.30%|   0.01%|   0.30%|  99.70%
     0|    11|   22|   0.40%|   0.02%|   0.39%|  99.60%
     0|    11|   23|   0.31%|   0.00%|   0.31%|  99.69%
     0|    12|   24|   0.33%|   0.01%|   0.32%|  99.67%
     0|    12|   25|   0.49%|   0.22%|   0.27%|  99.51%
     0|    13|   26|   0.29%|   0.02%|   0.27%|  99.71%
     0|    13|   27|   0.51%|   0.09%|   0.42%|  99.49%
     0|    14|   28|   0.49%|   0.12%|   0.38%|  99.51%
     0|    14|   29|   0.31%|   0.01%|   0.30%|  99.69%
     0|    15|   30|   0.74%|   0.10%|   0.64%|  99.26%
     0|    15|   31|   0.33%|   0.01%|   0.33%|  99.67%
     0|    16|   32|   0.36%|   0.00%|   0.36%|  99.64%
     0|    16|   33|   0.31%|   0.00%|   0.31%|  99.69%
     0|    17|   34|   0.30%|   0.01%|   0.29%|  99.70%
     0|    17|   35|   0.29%|   0.00%|   0.29%|  99.71%
     0|    18|   36|   0.28%|   0.01%|   0.27%|  99.72%
     0|    18|   37|   0.30%|   0.02%|   0.29%|  99.70%
     0|    19|   38|   0.30%|   0.00%|   0.30%|  99.70%
     0|    19|   39|   0.27%|   0.00%|   0.27%|  99.73%
     0|    20|   40|   0.31%|   0.01%|   0.30%|  99.69%
     0|    20|   41|   0.31%|   0.01%|   0.30%|  99.69%
     0|    21|   42|   0.28%|   0.00%|   0.28%|  99.72%
     0|    21|   43|   0.29%|   0.00%|   0.29%|  99.71%
     0|    22|   44|   0.35%|   0.02%|   0.34%|  99.65%
     0|    22|   45|   0.35%|   0.00%|   0.35%|  99.65%
     0|    23|   46|   0.32%|   0.00%|   0.32%|  99.68%
     0|    23|   47|   0.23%|   0.00%|   0.23%|  99.77%
     0|    24|   48|   0.32%|   0.00%|   0.32%|  99.68%
     0|    24|   49|   0.34%|   0.01%|   0.33%|  99.66%
     0|    25|   50|   0.28%|   0.01%|   0.27%|  99.72%
     0|    25|   51|   0.28%|   0.00%|   0.28%|  99.72%
     0|    26|   52|   0.29%|   0.01%|   0.29%|  99.71%
     0|    26|   53|   0.26%|   0.00%|   0.26%|  99.74%
     0|    27|   54|   0.32%|   0.01%|   0.31%|  99.68%
     0|    27|   55|   0.34%|   0.00%|   0.34%|  99.66%
     0|    28|   56|   0.36%|   0.01%|   0.36%|  99.64%
     0|    28|   57|   0.30%|   0.00%|   0.30%|  99.70%
     0|    29|   58|   0.39%|   0.00%|   0.39%|  99.61%
     0|    29|   59|   0.34%|   0.00%|   0.34%|  99.66%
     0|    30|   60|   0.37%|   0.01%|   0.36%|  99.63%
     0|    30|   61|   0.40%|   0.01%|   0.39%|  99.60%
     0|    31|   62|   0.31%|   0.00%|   0.31%|  99.69%
     0|    31|   63|   0.31%|   0.00%|   0.31%|  99.69%
     1|     0|    0|   0.29%|   0.01%|   0.29%|  99.71%
     1|     0|    1|   0.35%|   0.00%|   0.35%|  99.65%
     1|     1|    2|   0.33%|   0.03%|   0.30%|  99.67%
     1|     1|    3|   0.42%|   0.02%|   0.40%|  99.58%
     1|     2|    4|   0.29%|   0.00%|   0.29%|  99.71%
     1|     2|    5|   0.42%|   0.01%|   0.41%|  99.58%
     1|     3|    6|   0.33%|   0.01%|   0.33%|  99.67%
     1|     3|    7|   0.32%|   0.00%|   0.32%|  99.68%
     1|     4|    8|   0.32%|   0.03%|   0.29%|  99.68%
     1|     4|    9|   0.37%|   0.02%|   0.36%|  99.63%
     1|     5|   10|   0.29%|   0.02%|   0.28%|  99.71%
     1|     5|   11|   0.27%|   0.00%|   0.27%|  99.73%
     1|     6|   12|   0.29%|   0.01%|   0.28%|  99.71%
     1|     6|   13|   0.43%|   0.00%|   0.43%|  99.57%
     1|     7|   14|   1.24%|   0.01%|   1.23%|  98.76%
     1|     7|   15|   0.34%|   0.01%|   0.33%|  99.66%
     1|     8|   16|   0.29%|   0.02%|   0.27%|  99.71%
     1|     8|   17|   0.33%|   0.00%|   0.33%|  99.67%
     1|     9|   18|   0.40%|   0.02%|   0.38%|  99.60%
     1|     9|   19|   0.31%|   0.01%|   0.31%|  99.69%
     1|    10|   20|   0.36%|   0.00%|   0.36%|  99.64%
     1|    10|   21|   0.26%|   0.00%|   0.26%|  99.74%
     1|    11|   22|   0.34%|   0.00%|   0.34%|  99.66%
     1|    11|   23|   0.33%|   0.01%|   0.33%|  99.67%
     1|    12|   24|   0.28%|   0.00%|   0.28%|  99.72%
     1|    12|   25|   0.32%|   0.00%|   0.32%|  99.68%
     1|    13|   26|   0.34%|   0.01%|   0.33%|  99.66%
     1|    13|   27|   0.33%|   0.00%|   0.33%|  99.67%
     1|    14|   28|   0.34%|   0.00%|   0.34%|  99.66%
     1|    14|   29|   0.26%|   0.00%|   0.26%|  99.74%
     1|    15|   30|   0.34%|   0.00%|   0.34%|  99.66%
     1|    15|   31|   0.32%|   0.00%|   0.32%|  99.68%
     1|    16|   32|   0.26%|   0.00%|   0.26%|  99.74%
     1|    16|   33|   0.29%|   0.00%|   0.29%|  99.71%
     1|    17|   34|   0.36%|   0.01%|   0.35%|  99.64%
     1|    17|   35|   0.32%|   0.00%|   0.32%|  99.68%
     1|    18|   36|   0.38%|   0.01%|   0.37%|  99.62%
     1|    18|   37|   0.35%|   0.00%|   0.35%|  99.65%
     1|    19|   38|   0.29%|   0.01%|   0.29%|  99.71%
     1|    19|   39|   0.36%|   0.00%|   0.36%|  99.64%
     1|    20|   40|   0.29%|   0.00%|   0.29%|  99.71%
     1|    20|   41|   0.30%|   0.00%|   0.30%|  99.70%
     1|    21|   42|   0.36%|   0.00%|   0.36%|  99.64%
     1|    21|   43|   0.35%|   0.00%|   0.35%|  99.65%
     1|    22|   44|   0.26%|   0.00%|   0.26%|  99.74%
     1|    22|   45|   0.29%|   0.01%|   0.28%|  99.71%
     1|    23|   46|   0.31%|   0.00%|   0.31%|  99.69%
     1|    23|   47|   0.31%|   0.00%|   0.31%|  99.69%
     1|    24|   48|   0.27%|   0.00%|   0.27%|  99.73%
     1|    24|   49|   0.28%|   0.00%|   0.28%|  99.72%
     1|    25|   50|   0.31%|   0.00%|   0.31%|  99.69%
     1|    25|   51|   0.30%|   0.00%|   0.30%|  99.70%
     1|    26|   52|   0.30%|   0.01%|   0.29%|  99.70%
     1|    26|   53|   0.27%|   0.00%|   0.27%|  99.73%
     1|    27|   54|   0.34%|   0.00%|   0.34%|  99.66%
     1|    27|   55|   0.32%|   0.01%|   0.31%|  99.68%
     1|    28|   56|   0.24%|   0.00%|   0.24%|  99.76%
     1|    28|   57|   0.33%|   0.00%|   0.33%|  99.67%
     1|    29|   58|   0.27%|   0.02%|   0.24%|  99.73%
     1|    29|   59|   0.22%|   0.00%|   0.22%|  99.78%
     1|    30|   60|   0.32%|   0.00%|   0.32%|  99.68%
     1|    30|   61|   0.31%|   0.00%|   0.31%|  99.69%
     1|    31|   62|   0.27%|   0.00%|   0.27%|  99.73%
     1|    31|   63|   0.28%|   0.00%|   0.28%|  99.72%
     2|     0|    0|   0.36%|   0.01%|   0.36%|  99.64%
     2|     0|    1|   0.37%|   0.00%|   0.37%|  99.63%
     2|     1|    2|   0.34%|   0.01%|   0.33%|  99.66%
     2|     1|    3|   0.34%|   0.00%|   0.34%|  99.66%
     2|     2|    4|   0.36%|   0.00%|   0.36%|  99.64%
     2|     2|    5|   0.32%|   0.00%|   0.32%|  99.68%
     2|     3|    6|   0.31%|   0.00%|   0.31%|  99.69%
     2|     3|    7|   0.34%|   0.04%|   0.31%|  99.66%
     2|     4|    8|   0.30%|   0.01%|   0.29%|  99.70%
     2|     4|    9|   0.35%|   0.00%|   0.35%|  99.65%
     2|     5|   10|   0.35%|   0.00%|   0.35%|  99.65%
     2|     5|   11|   0.25%|   0.00%|   0.25%|  99.75%
     2|     6|   12|   0.58%|   0.23%|   0.34%|  99.42%
     2|     6|   13|   0.33%|   0.00%|   0.33%|  99.67%
     2|     7|   14|   0.54%|   0.13%|   0.41%|  99.46%
     2|     7|   15|   0.31%|   0.00%|   0.31%|  99.69%
     2|     8|   16|   0.31%|   0.01%|   0.30%|  99.69%
     2|     8|   17|   3.16%|   2.23%|   0.93%|  96.84%
     2|     9|   18|   0.38%|   0.03%|   0.35%|  99.62%
     2|     9|   19|   0.20%|   0.01%|   0.20%|  99.80%
     2|    10|   20|   0.35%|   0.01%|   0.34%|  99.65%
     2|    10|   21|   0.29%|   0.00%|   0.29%|  99.71%
     2|    11|   22|   0.29%|   0.01%|   0.28%|  99.71%
     2|    11|   23|   0.25%|   0.00%|   0.25%|  99.75%
     2|    12|   24|   0.28%|   0.00%|   0.28%|  99.72%
     2|    12|   25|   0.35%|   0.01%|   0.34%|  99.65%
     2|    13|   26|   0.31%|   0.02%|   0.29%|  99.69%
     2|    13|   27|   0.33%|   0.01%|   0.33%|  99.67%
     2|    14|   28|   0.37%|   0.03%|   0.34%|  99.63%
     2|    14|   29|   0.26%|   0.00%|   0.26%|  99.74%
     2|    15|   30|   0.32%|   0.00%|   0.32%|  99.68%
     2|    15|   31|   0.34%|   0.03%|   0.31%|  99.66%
     2|    16|   32|   0.26%|   0.03%|   0.23%|  99.74%
     2|    16|   33|   0.27%|   0.02%|   0.26%|  99.73%
     2|    17|   34|   0.28%|   0.01%|   0.27%|  99.72%
     2|    17|   35|   0.31%|   0.00%|   0.31%|  99.69%
     2|    18|   36|   0.29%|   0.04%|   0.25%|  99.71%
     2|    18|   37|   0.22%|   0.00%|   0.22%|  99.78%
     2|    19|   38|   0.30%|   0.00%|   0.30%|  99.70%
     2|    19|   39|   0.35%|   0.02%|   0.33%|  99.65%
     2|    20|   40|   0.32%|   0.01%|   0.31%|  99.68%
     2|    20|   41|   0.30%|   0.00%|   0.30%|  99.70%
     2|    21|   42|   0.35%|   0.01%|   0.34%|  99.65%
     2|    21|   43|   0.30%|   0.02%|   0.28%|  99.70%
     2|    22|   44|   0.39%|   0.02%|   0.37%|  99.61%
     2|    22|   45|   0.30%|   0.02%|   0.28%|  99.70%
     2|    23|   46|   0.38%|   0.03%|   0.35%|  99.62%
     2|    23|   47|   0.28%|   0.00%|   0.28%|  99.72%
     2|    24|   48|   0.37%|   0.00%|   0.37%|  99.63%
     2|    24|   49|   0.41%|   0.00%|   0.41%|  99.59%
     2|    25|   50|   0.26%|   0.00%|   0.26%|  99.74%
     2|    25|   51|   0.27%|   0.00%|   0.27%|  99.73%
     2|    26|   52|   0.31%|   0.00%|   0.31%|  99.69%
     2|    26|   53|   0.34%|   0.00%|   0.34%|  99.66%
     2|    27|   54|   0.34%|   0.00%|   0.34%|  99.66%
     2|    27|   55|   0.25%|   0.00%|   0.25%|  99.75%
     2|    28|   56|   0.31%|   0.01%|   0.30%|  99.69%
     2|    28|   57|   0.28%|   0.00%|   0.28%|  99.72%
     2|    29|   58|   0.28%|   0.00%|   0.28%|  99.72%
     2|    29|   59|   0.32%|   0.00%|   0.32%|  99.68%
     2|    30|   60|   0.37%|   0.07%|   0.30%|  99.63%
     2|    30|   61|   0.35%|   0.00%|   0.35%|  99.65%
     2|    31|   62|   0.28%|   0.01%|   0.28%|  99.72%
     2|    31|   63|   0.27%|   0.00%|   0.27%|  99.73%
-------------------------------------------------------
               avg.|   1.44%|   0.06%|   1.38%|  98.56%

Total IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |     21794156544 |      5320839 |      69.28 |   17736.09 | #1 (2.44TiB)
     1 |     21787013120 |      5319095 |      69.26 |   17730.27 | #1 (2.44TiB)
     2 |     21792616448 |      5320463 |      69.28 |   17734.83 | #1 (2.44TiB)
     3 |     21790244864 |      5319884 |      69.27 |   17732.90 | #1 (2.44TiB)
     4 |     18443841536 |      4502891 |      58.63 |   15009.60 | #1 (2.44TiB)
     5 |    105312731136 |     25711116 |     334.78 |   85703.50 | #1 (2.44TiB)
     6 |     21787398144 |      5319189 |      69.26 |   17730.59 | #1 (2.44TiB)
     7 |     21782720512 |      5318047 |      69.25 |   17726.78 | #1 (2.44TiB)
     8 |     21773647872 |      5315832 |      69.22 |   17719.40 | #1 (2.44TiB)
     9 |     21827018752 |      5328862 |      69.39 |   17762.83 | #1 (2.44TiB)
    10 |     21792174080 |      5320355 |      69.28 |   17734.47 | #1 (2.44TiB)
    11 |     21797863424 |      5321744 |      69.29 |   17739.10 | #1 (2.44TiB)
    12 |     21790552064 |      5319959 |      69.27 |   17733.15 | #1 (2.44TiB)
    13 |     21772021760 |      5315435 |      69.21 |   17718.07 | #1 (2.44TiB)
    14 |     21790994432 |      5320067 |      69.27 |   17733.51 | #1 (2.44TiB)
    15 |     21785804800 |      5318800 |      69.26 |   17729.29 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:      428820799488 |    104692578 |    1363.18 |  348974.38

Read IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     1 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     2 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     3 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     4 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     5 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     6 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     7 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     8 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     9 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    10 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    11 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    12 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    13 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    14 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
    15 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:                 0 |            0 |       0.00 |       0.00

Write IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |     21794156544 |      5320839 |      69.28 |   17736.09 | #1 (2.44TiB)
     1 |     21787013120 |      5319095 |      69.26 |   17730.27 | #1 (2.44TiB)
     2 |     21792616448 |      5320463 |      69.28 |   17734.83 | #1 (2.44TiB)
     3 |     21790244864 |      5319884 |      69.27 |   17732.90 | #1 (2.44TiB)
     4 |     18443841536 |      4502891 |      58.63 |   15009.60 | #1 (2.44TiB)
     5 |    105312731136 |     25711116 |     334.78 |   85703.50 | #1 (2.44TiB)
     6 |     21787398144 |      5319189 |      69.26 |   17730.59 | #1 (2.44TiB)
     7 |     21782720512 |      5318047 |      69.25 |   17726.78 | #1 (2.44TiB)
     8 |     21773647872 |      5315832 |      69.22 |   17719.40 | #1 (2.44TiB)
     9 |     21827018752 |      5328862 |      69.39 |   17762.83 | #1 (2.44TiB)
    10 |     21792174080 |      5320355 |      69.28 |   17734.47 | #1 (2.44TiB)
    11 |     21797863424 |      5321744 |      69.29 |   17739.10 | #1 (2.44TiB)
    12 |     21790552064 |      5319959 |      69.27 |   17733.15 | #1 (2.44TiB)
    13 |     21772021760 |      5315435 |      69.21 |   17718.07 | #1 (2.44TiB)
    14 |     21790994432 |      5320067 |      69.27 |   17733.51 | #1 (2.44TiB)
    15 |     21785804800 |      5318800 |      69.26 |   17729.29 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:      428820799488 |    104692578 |    1363.18 |  348974.38



ETW:
----

        Disk I/O
                Read: 776
                Write: 104783916


          ETW Buffer Settings & Statistics
--------------------------------------------------------
(KB)                           Buffers   (Secs)   (Mins)
Size  | Min |  Max  |  Free  | Written  | Flush    Age
138     384     406    384    117914         1        0

Allocated Buffers:      384
Lost Events:            0
Lost Log Buffers:       0
Lost Real Time Buffers: 0

[dl2n]

I'll speak to both observations I think you're trying to make.

Overall, you may simply be seeing a difference between Windows 2019 and 2025 as hosted on GCE. If after trying to control for a few factors (below) you still see this difference, following up with GCE (who may know about this, either as an issue at GCE or in Windows, other) and see if they can triage into the hosting environment.

NUMA node count.

Note: this doesn't affect results, its just documenting the system so we can better reason about them. DISKSPD only uses group number internally, and that aggregation looks the same on both sides.

I'd suggest using the Sysinternals CoreInfo tool as a check on DISKSPD, which I trust, but this is worth verifying on both 2019 and 2025

If both tools agree there may be an issue in how GCE's hypervisor is reporting topology and/or Window's interpretation of it. Reporting that in whichever way you find most appropriate would make sense, and I'd use CoreInfo's report to make it: CoreInfo will simply be the more familiar tool for all involved.

If CoreInfo disagrees with DISKSPD doesn't, we can try to figure out what's going on in DISKSPD's topology enumeration.

Results.

The load here is interesting in a few ways. Up front: -c is for creating file targets, it doesn't apply to physical disk targets (#1, physical disk 1). This should error, which is a bug we should fix.

Second - its sequential (the default). The 16 threads are going to independently start at offset zero of the physical disk (#1) and iteratively issue an IO, increment the for the next IO offset, issue there, and so forth. Independently means they'll all issue an IO at zero, then the next at 4k, the next at 8k. 16 IOs at zero, 16 IOs at 4K ... this would be unusual in practice (especially for writes). This is why you get 'WARNING: target access pattern will not be sequential, consider -si"; if you wanted a single sequentially advancing series of IOs, at least in time-order of the threads using interlocked operations to increment a shared offset between all 16 threads, -si is what you'd use. The threads would continue racing to dispatch, which could result in out-of-sequential order lower in the VM and/or host GCE stack, but any one offset of the file would receive only one IO (per complete sequential loop around the file) and it would likely be pretty close to actually sequential.

However, 16 threads doing cooperative sequential is unusual. Sequential is near universally a single-thread operation. The reason -si is present is in case we want to go faster with a second (maybe third?) thread given some limit of CPU speed v. storage speed. This doesn't model a normal workload.

Third, depending on how the disk was initialized (trim/unmap), reused or not between the two cases if on the same VM container and allocated disk "device", GCE and the Google storage backend may be doing very different things between the two runs. I'd suggest confirming the total history and, best, either pre-write the physical disk OR in some other way guarantee it is in a reproducibly stable initial condition between the two. For instance, if you really are wanting to stress GCE's first writes to the device, reallocate it each time.

[gaoyefei]

Thank you Dan. A couple of updates:

1. CoreInfo agrees with diskspd. I'll follow up with GCE and MSFT Windows teams.
2. I modified the test command a bit: diskspd -eDISK_IO -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t16 -si #1\testfile.dat (I assumed that's the right format to specify a file because I didn't get any error). Numbers on both versions went down to: 2019: 137K, 2025: 242K. What params would you suggest me to tweak if I'd like to find out the absolute limits of the disk on these Windows systems? Any suggestions for read IOPS too?(next on my list)
3. Wanted to clarify that when I say 'same VM', they're not the exact same instance. Instead I created these 2 VMs with the exact same VM and disk spec. The disks should be in the same state when I started the testing on both, in parallel.

[dl2n]

Reading back, I should clarify - the fact 2025 lost the NUMA node reporting could definitely affect results, as a matter of whole-system behavior that would enlighten with NUMA topology info. What I'd meant to say was that it wouldn't affect DISKSPDs load pattern, thread layout. Anyway, this is absolutely a good thing to take to GCE who may then engage Microsoft to help figure out the reporting difference. With this core count there is definitely NUMA somewhere.

No; thats not the format for a file. Another bug. I suspect the target parser is just interpreting that as PD 1 (#1) and ignoring the rest. If you want a file, put a filesystem on the device. New-Volume at the powershell cmdline or other method, any works.

The usual way to lay out this many independent sequential threads is to use -T to space out their initial offsets. This has a rough way of translating to a proper workload, like sixteen independent streams of data landing on the device. Take the size / #threads. If its 1TB, -T64G to space them evenly. Mental model is like a horse race, you're spacing them around the (single lane) track as opposed to having them all on top of each other, either actually (-s/default) or wrestling out who isues at 0, 4K, 8K, etc.

However:

In general: small IOs are random (pagefaulting db/memory), large IOs are individually sequential (copy/stream) but may become random at the device level (multiples). Specific cases are specific cases.

If you're trying for write IOPS as opposed to write bandwidth, I'd suggest doing this either through a file of O(10)GB or limit the range of the physical device (-B). This tries to say something about write workingset. Alternately, you can explore different set points. Do one at 10GB, another at 100GB. You may see different behavior with the metadata stress this places on the backend (you should also be able to see this on most SSD).

Then do the same thing for reads. Do you care about mixed loads? (-w30 -b4k -r ...)

But, for both: pre-write the range of the target (either the entire file, or the portion of the device) with sequential large IO (say -t1 -o4 -B1m ...) sufficient to write through it at least once or twice. This maps over to some industry methodology guidance SNIA SSD Performance and all the basic rationale for SSD applies to aggregate cloud storage. You will see different behavior at time zero (fresh allocated never written) v. sequentially written v. given load applied for some period of time. Getting to controllable initial conditions will save/focus questions and let you explore more deliberately.

[gaoyefei]

Thanks for the suggestions, Dan. I have been trying those.

One more question I'd like to ask is, on Windows 2025, I was able to get some high output number unexpectedly when added the -ag option:

Original command:
diskspd -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t4 -r #1 --- write IOPS=226K

With -ag:
diskspd -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t4 -r -ag0,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18 #1 --- write IOPS=377K

Do you know what happened here? Why forcing some cores in 1 cpu group would increase the output that much? From diskspd output, it doesn't look like the specified cores got busy anyway:

diskspd -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t4 -r -ag0,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18 #1

Command Line: diskspd -w100 -d300 -W10s -Sh -c512G -b4K -o64 -t4 -r -ag0,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18 #1

Input parameters:

        timespan:   1
        -------------
        duration: 300s
        warm up time: 10s
        cool down time: 0s
        random seed: 0
        advanced affinity round robin (group/core): 0/2, 0/3, 0/4, 0/5, 0/6, 0/7, 0/8, 0/9, 0/10, 0/11, 0/12, 0/13, 0/14, 0/15, 0/16, 0/17, 0/18
        path: '#1'
                think time: 0ms
                burst size: 0
                software cache disabled
                hardware write cache disabled, writethrough on
                performing write test
                block size: 4KiB
                using random I/O (alignment: 4KiB)
                number of outstanding I/O operations per thread: 64
                threads per file: 4
                using I/O Completion Ports
                IO priority: normal

System information:

        computer name: testcase-148196-1755643804-0
        start time: 2025/09/18 18:59:54 UTC

        cpu count:              192
        core count:             96
        group count:            3
        node count:             1
        socket count:           1
        heterogeneous cores:    n

        active power scheme:    High performance (8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c)

Results for timespan 1:
*******************************************************************************

actual test time:       300.00s
thread count:           4

Group | Core | CPU |  Usage |  User  | Kernel |  Idle
-------------------------------------------------------
     0|     0|    0|   1.24%|   0.01%|   1.23%|  98.76%
     0|     0|    1|   0.27%|   0.00%|   0.27%|  99.73%
     0|     1|    2|  47.71%|   1.84%|  45.87%|  52.29%
     0|     1|    3|  47.86%|   2.04%|  45.83%|  52.14%
     0|     2|    4|  95.57%|   0.20%|  95.36%|   4.43%
     0|     2|    5|  83.01%|   1.40%|  81.60%|  16.99%
     0|     3|    6|   0.79%|   0.14%|   0.65%|  99.21%
     0|     3|    7|   0.41%|   0.05%|   0.36%|  99.59%
     0|     4|    8|   0.47%|   0.04%|   0.43%|  99.53%
     0|     4|    9|   0.33%|   0.00%|   0.33%|  99.67%
     0|     5|   10|   0.51%|   0.03%|   0.47%|  99.49%
     0|     5|   11|   0.35%|   0.00%|   0.35%|  99.65%
     0|     6|   12|   0.41%|   0.01%|   0.40%|  99.59%
     0|     6|   13|   0.46%|   0.02%|   0.44%|  99.54%
     0|     7|   14|   0.41%|   0.03%|   0.39%|  99.59%
     0|     7|   15|   0.36%|   0.02%|   0.34%|  99.64%
     0|     8|   16|   0.32%|   0.01%|   0.31%|  99.68%
     0|     8|   17|   0.28%|   0.01%|   0.28%|  99.72%
     0|     9|   18|   0.31%|   0.01%|   0.30%|  99.69%
     0|     9|   19|   0.31%|   0.01%|   0.30%|  99.69%
     0|    10|   20|   0.32%|   0.01%|   0.31%|  99.68%
     0|    10|   21|   0.27%|   0.00%|   0.27%|  99.73%
     0|    11|   22|   0.33%|   0.01%|   0.32%|  99.67%
     0|    11|   23|   0.30%|   0.01%|   0.30%|  99.70%
     0|    12|   24|   0.31%|   0.01%|   0.31%|  99.69%
     0|    12|   25|   0.28%|   0.01%|   0.28%|  99.72%
     0|    13|   26|   0.35%|   0.01%|   0.34%|  99.65%
     0|    13|   27|   0.34%|   0.01%|   0.33%|  99.66%
     0|    14|   28|   0.32%|   0.01%|   0.31%|  99.68%
     0|    14|   29|   0.33%|   0.00%|   0.33%|  99.67%
     0|    15|   30|   0.39%|   0.01%|   0.38%|  99.61%
     0|    15|   31|   0.35%|   0.01%|   0.34%|  99.65%
     0|    16|   32|   0.39%|   0.00%|   0.39%|  99.61%
     0|    16|   33|   0.41%|   0.00%|   0.41%|  99.59%
     0|    17|   34|   0.37%|   0.02%|   0.35%|  99.63%
     0|    17|   35|   0.33%|   0.00%|   0.33%|  99.67%
     0|    18|   36|   0.37%|   0.01%|   0.36%|  99.63%
     0|    18|   37|   0.32%|   0.00%|   0.32%|  99.68%
     0|    19|   38|   0.38%|   0.00%|   0.38%|  99.62%
     0|    19|   39|   0.42%|   0.01%|   0.41%|  99.58%
     0|    20|   40|   0.42%|   0.00%|   0.42%|  99.58%
     0|    20|   41|   0.38%|   0.00%|   0.38%|  99.62%
     0|    21|   42|   0.36%|   0.00%|   0.36%|  99.64%
     0|    21|   43|   0.36%|   0.01%|   0.35%|  99.64%
     0|    22|   44|   0.39%|   0.00%|   0.39%|  99.61%
     0|    22|   45|   0.37%|   0.00%|   0.37%|  99.63%
     0|    23|   46|   0.39%|   0.00%|   0.39%|  99.61%
     0|    23|   47|   0.39%|   0.00%|   0.39%|  99.61%
     0|    24|   48|   0.33%|   0.00%|   0.33%|  99.67%
     0|    24|   49|   0.32%|   0.00%|   0.32%|  99.68%
     0|    25|   50|   0.35%|   0.01%|   0.34%|  99.65%
     0|    25|   51|   0.34%|   0.00%|   0.34%|  99.66%
     0|    26|   52|   0.40%|   0.00%|   0.40%|  99.60%
     0|    26|   53|   0.43%|   0.00%|   0.43%|  99.57%
     0|    27|   54|   0.31%|   0.00%|   0.31%|  99.69%
     0|    27|   55|   0.31%|   0.00%|   0.31%|  99.69%
     0|    28|   56|   0.32%|   0.00%|   0.32%|  99.68%
     0|    28|   57|   0.32%|   0.00%|   0.32%|  99.68%
     0|    29|   58|   0.34%|   0.00%|   0.34%|  99.66%
     0|    29|   59|   0.33%|   0.00%|   0.33%|  99.67%
     0|    30|   60|   0.32%|   0.00%|   0.32%|  99.68%
     0|    30|   61|   0.34%|   0.00%|   0.34%|  99.66%
     0|    31|   62|   0.40%|   0.00%|   0.40%|  99.60%
     0|    31|   63|   0.36%|   0.00%|   0.36%|  99.64%
     1|     0|    0|   0.23%|   0.00%|   0.23%|  99.77%
     1|     0|    1|   0.26%|   0.01%|   0.26%|  99.74%
     1|     1|    2|   0.42%|   0.00%|   0.42%|  99.58%
     1|     1|    3|   0.36%|   0.01%|   0.35%|  99.64%
     1|     2|    4|   0.38%|   0.00%|   0.38%|  99.62%
     1|     2|    5|   0.34%|   0.00%|   0.34%|  99.66%
     1|     3|    6|   0.39%|   0.00%|   0.39%|  99.61%
     1|     3|    7|   0.34%|   0.00%|   0.34%|  99.66%
     1|     4|    8|   0.39%|   0.01%|   0.39%|  99.61%
     1|     4|    9|   0.35%|   0.00%|   0.35%|  99.65%
     1|     5|   10|   0.30%|   0.00%|   0.30%|  99.70%
     1|     5|   11|   0.35%|   0.00%|   0.35%|  99.65%
     1|     6|   12|   0.34%|   0.00%|   0.34%|  99.66%
     1|     6|   13|   0.36%|   0.00%|   0.36%|  99.64%
     1|     7|   14|   0.32%|   0.00%|   0.32%|  99.68%
     1|     7|   15|   0.35%|   0.01%|   0.35%|  99.65%
     1|     8|   16|   0.35%|   0.00%|   0.35%|  99.65%
     1|     8|   17|   0.32%|   0.00%|   0.32%|  99.68%
     1|     9|   18|   0.36%|   0.01%|   0.35%|  99.64%
     1|     9|   19|   0.34%|   0.01%|   0.33%|  99.66%
     1|    10|   20|   0.36%|   0.00%|   0.36%|  99.64%
     1|    10|   21|   0.35%|   0.00%|   0.35%|  99.65%
     1|    11|   22|   0.36%|   0.00%|   0.36%|  99.64%
     1|    11|   23|   0.35%|   0.00%|   0.35%|  99.65%
     1|    12|   24|   0.35%|   0.00%|   0.35%|  99.65%
     1|    12|   25|   0.36%|   0.00%|   0.36%|  99.64%
     1|    13|   26|   0.35%|   0.00%|   0.35%|  99.65%
     1|    13|   27|   0.31%|   0.00%|   0.31%|  99.69%
     1|    14|   28|   0.34%|   0.00%|   0.34%|  99.66%
     1|    14|   29|   0.35%|   0.01%|   0.35%|  99.65%
     1|    15|   30|   0.39%|   0.00%|   0.39%|  99.61%
     1|    15|   31|   0.41%|   0.00%|   0.41%|  99.59%
     1|    16|   32|   0.33%|   0.02%|   0.32%|  99.67%
     1|    16|   33|   0.46%|   0.02%|   0.44%|  99.54%
     1|    17|   34|   0.34%|   0.03%|   0.31%|  99.66%
     1|    17|   35|   0.26%|   0.00%|   0.26%|  99.74%
     1|    18|   36|   0.29%|   0.01%|   0.29%|  99.71%
     1|    18|   37|   0.31%|   0.00%|   0.31%|  99.69%
     1|    19|   38|   0.28%|   0.00%|   0.28%|  99.72%
     1|    19|   39|   0.34%|   0.02%|   0.33%|  99.66%
     1|    20|   40|   0.33%|   0.01%|   0.32%|  99.67%
     1|    20|   41|   0.33%|   0.00%|   0.33%|  99.67%
     1|    21|   42|   0.33%|   0.01%|   0.33%|  99.67%
     1|    21|   43|   0.29%|   0.00%|   0.29%|  99.71%
     1|    22|   44|   0.38%|   0.00%|   0.38%|  99.62%
     1|    22|   45|   0.43%|   0.00%|   0.43%|  99.57%
     1|    23|   46|   0.31%|   0.02%|   0.29%|  99.69%
     1|    23|   47|   0.37%|   0.03%|   0.34%|  99.63%
     1|    24|   48|   0.29%|   0.00%|   0.29%|  99.71%
     1|    24|   49|   0.30%|   0.00%|   0.30%|  99.70%
     1|    25|   50|   0.36%|   0.01%|   0.35%|  99.64%
     1|    25|   51|   0.31%|   0.00%|   0.31%|  99.69%
     1|    26|   52|   0.28%|   0.00%|   0.28%|  99.72%
     1|    26|   53|   0.29%|   0.00%|   0.29%|  99.71%
     1|    27|   54|   0.32%|   0.00%|   0.32%|  99.68%
     1|    27|   55|   0.33%|   0.00%|   0.33%|  99.67%
     1|    28|   56|   0.29%|   0.01%|   0.29%|  99.71%
     1|    28|   57|   0.26%|   0.00%|   0.26%|  99.74%
     1|    29|   58|   0.36%|   0.00%|   0.36%|  99.64%
     1|    29|   59|   0.39%|   0.00%|   0.39%|  99.61%
     1|    30|   60|   0.32%|   0.00%|   0.32%|  99.68%
     1|    30|   61|   0.30%|   0.00%|   0.30%|  99.70%
     1|    31|   62|   0.32%|   0.00%|   0.32%|  99.68%
     1|    31|   63|   0.28%|   0.00%|   0.28%|  99.72%
     2|     0|    0|   0.35%|   0.00%|   0.35%|  99.65%
     2|     0|    1|   0.39%|   0.00%|   0.39%|  99.61%
     2|     1|    2|   0.29%|   0.01%|   0.28%|  99.71%
     2|     1|    3|   0.27%|   0.00%|   0.27%|  99.73%
     2|     2|    4|   0.31%|   0.00%|   0.31%|  99.69%
     2|     2|    5|   0.32%|   0.00%|   0.32%|  99.68%
     2|     3|    6|   0.30%|   0.00%|   0.30%|  99.70%
     2|     3|    7|   0.31%|   0.00%|   0.31%|  99.69%
     2|     4|    8|   0.34%|   0.00%|   0.34%|  99.66%
     2|     4|    9|   0.36%|   0.00%|   0.36%|  99.64%
     2|     5|   10|   0.34%|   0.00%|   0.34%|  99.66%
     2|     5|   11|   0.36%|   0.00%|   0.36%|  99.64%
     2|     6|   12|   0.35%|   0.00%|   0.35%|  99.65%
     2|     6|   13|   0.36%|   0.00%|   0.36%|  99.64%
     2|     7|   14|   0.26%|   0.00%|   0.26%|  99.74%
     2|     7|   15|   0.25%|   0.00%|   0.25%|  99.75%
     2|     8|   16|   0.36%|   0.00%|   0.36%|  99.64%
     2|     8|   17|   0.41%|   0.00%|   0.41%|  99.59%
     2|     9|   18|   0.39%|   0.01%|   0.38%|  99.61%
     2|     9|   19|   0.36%|   0.00%|   0.36%|  99.64%
     2|    10|   20|   0.29%|   0.00%|   0.29%|  99.71%
     2|    10|   21|   0.28%|   0.00%|   0.28%|  99.72%
     2|    11|   22|   0.30%|   0.00%|   0.30%|  99.70%
     2|    11|   23|   0.27%|   0.00%|   0.27%|  99.73%
     2|    12|   24|   0.30%|   0.00%|   0.30%|  99.70%
     2|    12|   25|   0.27%|   0.00%|   0.27%|  99.73%
     2|    13|   26|   0.35%|   0.01%|   0.34%|  99.65%
     2|    13|   27|   0.32%|   0.00%|   0.32%|  99.68%
     2|    14|   28|   0.36%|   0.00%|   0.36%|  99.64%
     2|    14|   29|   0.36%|   0.00%|   0.36%|  99.64%
     2|    15|   30|   0.30%|   0.00%|   0.30%|  99.70%
     2|    15|   31|   0.28%|   0.00%|   0.28%|  99.72%
     2|    16|   32|   0.32%|   0.00%|   0.32%|  99.68%
     2|    16|   33|   0.38%|   0.00%|   0.38%|  99.62%
     2|    17|   34|   0.34%|   0.02%|   0.32%|  99.66%
     2|    17|   35|   0.33%|   0.00%|   0.33%|  99.67%
     2|    18|   36|   0.32%|   0.01%|   0.32%|  99.68%
     2|    18|   37|   0.33%|   0.00%|   0.33%|  99.67%
     2|    19|   38|   0.34%|   0.00%|   0.34%|  99.66%
     2|    19|   39|   0.34%|   0.00%|   0.34%|  99.66%
     2|    20|   40|   0.32%|   0.00%|   0.32%|  99.68%
     2|    20|   41|   0.34%|   0.00%|   0.34%|  99.66%
     2|    21|   42|   0.35%|   0.00%|   0.35%|  99.65%
     2|    21|   43|   0.35%|   0.00%|   0.35%|  99.65%
     2|    22|   44|   0.31%|   0.00%|   0.31%|  99.69%
     2|    22|   45|   0.28%|   0.00%|   0.28%|  99.72%
     2|    23|   46|   0.32%|   0.00%|   0.32%|  99.68%
     2|    23|   47|   0.32%|   0.00%|   0.32%|  99.68%
     2|    24|   48|   0.30%|   0.01%|   0.30%|  99.70%
     2|    24|   49|   0.29%|   0.01%|   0.28%|  99.71%
     2|    25|   50|   0.40%|   0.01%|   0.39%|  99.60%
     2|    25|   51|   0.45%|   0.00%|   0.45%|  99.55%
     2|    26|   52|   0.38%|   0.00%|   0.38%|  99.62%
     2|    26|   53|   0.33%|   0.00%|   0.33%|  99.67%
     2|    27|   54|   0.34%|   0.00%|   0.34%|  99.66%
     2|    27|   55|   0.33%|   0.00%|   0.33%|  99.67%
     2|    28|   56|   0.29%|   0.00%|   0.29%|  99.71%
     2|    28|   57|   0.32%|   0.00%|   0.32%|  99.68%
     2|    29|   58|   0.36%|   0.01%|   0.35%|  99.64%
     2|    29|   59|   0.33%|   0.00%|   0.33%|  99.67%
     2|    30|   60|   0.38%|   0.01%|   0.37%|  99.62%
     2|    30|   61|   0.36%|   0.00%|   0.36%|  99.64%
     2|    31|   62|   0.27%|   0.00%|   0.27%|  99.73%
     2|    31|   63|   0.30%|   0.00%|   0.30%|  99.70%
-------------------------------------------------------
               avg.|   1.77%|   0.03%|   1.74%|  98.23%

Total IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |    124669521920 |     30436895 |     396.31 |  101455.95 | #1 (2.44TiB)
     1 |    124889370624 |     30490569 |     397.01 |  101634.86 | #1 (2.44TiB)
     2 |     61092290560 |     14915110 |     194.21 |   49716.85 | #1 (2.44TiB)
     3 |    152210747392 |     37160827 |     483.86 |  123868.98 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:      462861930496 |    113003401 |    1471.39 |  376676.64

Read IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     1 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     2 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
     3 |               0 |            0 |       0.00 |       0.00 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:                 0 |            0 |       0.00 |       0.00

Write IO
thread |       bytes     |     I/Os     |    MiB/s   |  I/O per s |  file
------------------------------------------------------------------------------
     0 |    124669521920 |     30436895 |     396.31 |  101455.95 | #1 (2.44TiB)
     1 |    124889370624 |     30490569 |     397.01 |  101634.86 | #1 (2.44TiB)
     2 |     61092290560 |     14915110 |     194.21 |   49716.85 | #1 (2.44TiB)
     3 |    152210747392 |     37160827 |     483.86 |  123868.98 | #1 (2.44TiB)
------------------------------------------------------------------------------
total:      462861930496 |    113003401 |    1471.39 |  376676.64